Cellulose envelop for elements of storage batteries.



No. 646,923. Patented Apr. 3, won.

E. A. SPEBRY. CELLULOSE ENVELUP FUR ELEMENTS 0F STORAGE BATTEBIES.

(Ayplication filed Oct. '7, 1899.}

(No Model.)

' 'm: Nomys PETERS C0 PHOTO-ILXTHQ, WASHINGTON, u. c

MED STATES PATENT Omen.

ELMER A. SPERRY, F CLEVELAND, OHIO.

CELLULOSE ENVELOP FOR ELEMENTS OF STORAGE BATTERIES.

SPECIFICATION forming part of Letters Patent No. 646,923, dated April 3,1900.

Application filed October '7, 1899- Serial No. 732,859. (No specimens.)

T0 aZZ whom it may concern.-

Beitknown that I, ELMER A. SPERRY, a citizen of the United States,residing at Cleveland, in the county of Cuyahoga and State of Ohio, haveinvented certain new and useful Improvements in Cellulose NitrateFabrics- Oellulose Envelops for Elements of Storage Batteries-of whichthe following is a specification.

My invention relates to separators or en velops for elements ofbatteries; and it consists in an improved material of which suchseparators or envelops may be constructed,

' the characteristics of which are fully described in the followingspecification, the novelty being pointed out in the claims heretoannexed, being also illustrated in the accom panying drawings, in which-Figure 1 of the accompanying drawings shows one form of the envelop ordiaphragm. Fig. 2 shows an edge or sectional view. Fig. 3 is also anedge or sectionalview showing wavy or corrugated surface.

Similar letters of reference refer to like parts throughout the figures.

In the drawings the diaphragm or separator is illustrated at A. It isshown as made up of a plurality of layers, the drawings simplyindicating that upon each side of the pyroxylin fabric B there is alayer of suitable fiber O, the nature of which is more fully pointed outin the specification.

In Fig. 3 the undulating, corrugated, or ribbed surface is indicated bythe ribs shown by projections a a, 850.

It has been found that in battery elements, especially storage-batteryelements, the ac tive material more or less readily disintegrates andtends to fall from the plate, accumulating in the bottom of the cell. Ithas, furthermore, been found that with an envelop if properlyconstructed from substance permeable to the electrolyte and such as notto interfere with the traverse of the ions this material or substancemay be retained mechanthis purpose I have used cellulose of special formand of such a material and structure as will retain its rigidity andinflexibility to a considerable degree. This I have found is bestattained by using pure cellulose and in treating fiber in which thenon-cellulosic constituents belong to the class of aldehydes and which Iremove by the action of sulfurous acid, yielding thereby a fiber inwhich the ordinary strength is entirely preserved and one that can beused for the purpose and in the manner described. I have found thatfibers treated with alkaline processes are short, brittle, and notsuitable for battery purposes, especially when used in connection with asulfuric-acid electrolyte. It has also been found that the individualfibers are rendered to a considerable extent more inert by beingsubjected to the action of sulfurous acid a second time with anintervening washing. To

distinguish this product from the ordinary and less inert forms ofsulfite fiber, I call it double sulfite fiber. In this way the aldehydesare more thoroughly eliminated and the filber is found to be almostperfectly inert in the liquid electrolyte described and unaffected bythe nascent oxygen and hydrogen developed at the poles, While this fiberis found to yield excellent results, especially when corrugated orribbed and treated and utilized as described in my application forUnited States Patent, Serial No. 689,057, filed Au gust 19, 1898. I'have found, however, that the stiffness and general durability of the envelop may be still further improved by the addition of pyroxylin. This Iprefer to make of a fabric consisting of cotton-as, for instance,sea-island cotton which is prepared in a peculiar manner in regard tothree features.

First. The nitrogenizing process is carried on to a point where just theright amount of nitrogen is present, giving the fiber of the fabric amaximum tenacity, as is well known in the art.

Second. The flexibility of the pyroxylin fiber, and therefore of thefabric, I find to be somewhat improved by adding a trifle of vaseline;but with some processes of pulping and mixture with the cellulose thisis found to be objectionable. In some instances, however, the pyroxylinfabric so treated may be used with success.

Third. During the latter part of the process or, in fact, in any part ofthe process of nitrogenizing or in the washing the fabric is treatedwith just sufficient nitrobenzol or equivalent to render the same notspontaneously explosive; but this is not necessary to the invention, andsome of the special processes and treatment described in connection withthe preparation of pyroxylin fabric may be eliminated and others used,and the invention extends to such use.

The cotton fabric of which the cellulose is made is preferably wovenwith open'mesh and light, similar to ordinary cheese-cloth or the like,although anyfabric that is found to be especially applicable to anyparticular purpose may be employed. There are numerous ways in which thecellulose fiber may be applied commingled or interspersed-as, forinstance, in a plurality of layerswith this network or nets ofpyroxylin. For instance, it

, may be applied in sheet form upon one or both sides or in alternatinglayers or cemented with suitable cementfor instance, such a one as isnot acted upon by the electrolyte; but I prefer to apply it in the pulpform and find that, while it is advisable to have an equal applicationupon either side of the fabric, the pulp easily penetrates and thefabric sinks into the mass of pulp when the flotation in thematrix-machine is applied to one side only of the fabric. When appliedto both sides of the fabric, the machine is prepared with a plurality ofcylinders, where the two or more filaments of the cellulose are floatedout and separately applied upon either side of the pyroxylin fabric orfabrics, all going forward from this point on as a single sheet or mass.

For the purpose of increasing the rigidity of the sheet the appliedfibers are preferably longer than the distance across the mesh oropenings in the pyroxylin layer or mass in one line more than another.In addition to the means resorted to, presently to be described, I findthat this result may be facilitated by selecting a fabric or preparing aspecial fabric for the nitrogenizing process which shall have more orlarger threads in its woof than in its warp, or vice versa, and thenstill aiding the process by floating the cellulose fibers parallel tothe direction taken up by the larger threads within the fabric now to bedescribed.

It is sometimes found desirable to increase the rigidity orinflexibility of the sheet or envelop in one line more than anotherwithin the sheet. This I have been enabled to accomplish by a unilineardisposition of the cellulose fibers within the sheet, accomplished,

preferably, by a flowing or so directing the water upon the pulping ormatrix blanket that the majority of the cellulose fibers will take up asingle unilinear direction within such matrix and eventually within thesheet. This does not mean that all the cellulose fibers in the sheet areparallel; but there is a direction easily discernible which indicatesthe direction of more fibers than any other line within the sheet, andthe sheet is found to be more rigid to a bending moment applied at rightangles to this line. lVhen the matrix so constructed is prepared for usein sheet form, I prefer to subject it toa consid-' erable pressure,which may be done in any well-known Way, either by passing it throughrollers or between plates at any point in the process of manufacture,and I find that the density and stability of the sheet after subon thepulping-machine or by corrugated rollers in the rolling process abovereferred to. I do not care to limit myself to anyparticular process ofcorrugation or style or configuration of the irregularity of surfaceconstituting the corrugation.

I have employed the term pyroxylin as indicating the various forms ofcellulose nitrates or nitrogen cellulose. The hexanitrate and others inthe series may be employed. The only point as to the exact constituentsof the compound is that which, taken with the particular fiberoriginally employed, will give a nitrogen-cellulose of the maximumstrength, durability, and tenacity. The reason why I prefer to use theword pyroxylin in this case as a generic term is that in its preferredform the nitrocellulose is not spontaneously explosive and as hereinused is only considered in connection with its mechanical properties.The term guncotton would be misleading, and again using the generic termnitrogen cellulose it brings throughout the specification and claims injuxtaposition two expressions containing the word cellulose, which mightlead to confusion.

It will be readily understood that while it is designed to use the aboveparts in the relation shown, yet some may be used without the others,and the invention extends to such use. It will furthermore bereadilyunderstood that whilethe detailed construction has been describedwith more or less minuteness, yet the invention should be in nowiserestricted to the exact methods and details described, but rathershould be limited only in scope, as indicated in the claims.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

1. An envelop or separator for elements of batteries, consisting of alayer of pyroxylin fabric and a layer of cellulose.

2. An envelop or separator for elements of batteries, consisting of alayer of pyroxylin fabric and a layer of cellulose on each side of thefabric.

3. A diaphragm for batteries, consisting of a layer of pyroxylin fabricand a layer of cellulose composed of fibers longer than the distanceacross the openings or mesh of the pyroxylin fabric.

4. An envelop or separator for elements of batteries, consisting of alayer of pyroxylin fabric and a layer of sulfite fiber.

5. An envelop or separator for elements of batteries, consisting of alayer of pyroxylin fabric, and a layer of cellulose in sheet form,

having one or more surfaces, ribbed or corrugated.

6. An envelop or separator for elements of batteries, consisting of acompressed mass in sheet form, constituted of a layer of pyroxylinfabric and a layer of cellulose.

7. An envelop or separator for elements of batteries, consisting of alayer of pyroxylin fabric and a layer of cellulose fiber, the fibersbeing parallelly disposed Within the mass and in line with the warp orWoof of the fabric.

8. An envelop or separator for elements of batteries, consisting of alayer of pyroxylin fabric, in which the warp and woof are dissimilar asto coarseness or Weight, and a layer of cellulose.

9. An envelop or separator for elements of batteries, consisting of alayer of pyroxylin fabric, in which the warp and Woof are dissimilar asto coarseness or weight, and a layer of cellulose fiber, the fiber beingparallelly disposed within the mass.

10. An envelop or separator for elements of batteries, consisting of alayer of pyroxylin fabric, in which the Warp and woof are dissimilar asto coarseness or weight, and a layer of cellulose fiber, the fibersbeing disposed parallel to the heavier texture elements.

11. As an article of manufacture, a separator or envelop for elements ofbatteries, consisting of a network or mesh of cellulose nitrate fiber,impermeable to the electrolyte, to which it is applied and a layer ofcellulose fiber, permeable to the electrolyte, substantially asspecified.

12. A diaphragm for batteries, consisting of an open-meshed pyroxylinfabric, the fibers of which are impermeable to the electrolyte,associated With a suitable fiber permeable to the electrolyte, forincreasing the mass of the diaphragm.

13. A diaphragm for a battery, consisting of an open-mesh pyroxylinfabric, insoluble in the electrolyte, associated with suitable non-wovenfiber for increasing the mass of the diaphragm.

ELMER A. SPERRY.

Witnesses:

W. S. ROGERS, H. W. LAMBLEY.

